Field of Invention
This invention is related to firearms and specifically a means to tighten the upper and lower receiver subassemblies in auto-loading firearms.
Background
In autoloading firearms with upper and lower receivers there is not a suitable way to allow the upper receiver sub-assembly of the firearm to maintain a connection to the lower receiver sub-assembly that is reliably snug and without any “play” or “slop” between the two primary firearm sub-assemblies. A tight connection between the two sub-assemblies is desired by precision shooters in order to keep the upper receiver sub-assembly from “torqueing” on the operator when being fired, which is otherwise known to result in down-range projectile accuracy degradation.
Because of varying tolerances in the manufacturing of upper and lower receivers it is nearly impossible to achieve a suitable fit. Loose fitting receivers will make even the best custom built rifle less than ideal for precision shooting. Many shooters solve the problem with a wedge under the upper receiver lug when the receiver is closed. It serves the purpose but is cumbersome to use. Among others, the company Tactable Innovations, Inc. makes a system employing a nylon tipped Allen wrench drive screw that, and with partial disassembly of the lower receiver subassembly, can be manually adjusted. The tensioning screw allows the user to exert pressure on the upper receiver for a more controlled upper receiver fit. While this tensioning screw works, it is more complex and failure-prone than is convenient and requires manual adjustment and maintenance, which includes substantial disassembly of the firearm.
The present invention provides a better solution.